Electric switch



Feb. 24, 1931. BARR 1,793,989

ELECTRIC SWITCH Filed July 23, 1923 Patented Feb. 24, 1931 UNITED STATES PATENT OFFICE JOHN M. BARR, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE LOUIS ALLIS COM- PANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN ELECTRIC SWITCH Application filed July 23,

This invention relates to an electric switch.

The switch to which the, invention applies in particular has a rotary drum, contact segments arranged upon the drum and insulated o from each other, and a brush to make electrical contact with the contact segments successively as the drum rotates.

An object of the invention is to eliminate sparking in switches of this character.

Another object is to vary the time during which the brush is in contact with each segment.

Another object is to accelerate thedrum momentarily as the brush. crosses the gap 1 between the contact segments.

Other objects and advantages will appear hereinafter.

According to one aspect of the invention, the drum is momentarily retarded as the 2d brush is about to break contact with one contact segment, and it is then suddenly accelera-ted momentarily as the brush breaks contact with one segment and makes contactv with the other.

The invention is exemplified in the accompanying drawing in which the views are as follows:

Fig. 1 is a side elevation of a switch embodying the invention.

Fig. 2 is an end elevation thereof.

Fig. 3 is a side elevation showing the drum rotated 90 degrees from the position shown in Figure 1. I

Fig. 4 is a section on the line 44 of Fig ure 3.

The switch comprises an insulating drum 1 having two metallic segments 2 and 3 separated diagonally of the drum by insulation 4. Each segment has a raised portion or ridge 5 along one diagonal edge thereof in advance of the insulation. The drum is loosely mounted on a shaft 6 which is rotated at a constant speed in any suitable manner as by a worm and pinion 7 driven from a motor shaft 8 by a belt and pulley 9.

A collar 10 is fixed for rotation with the shaft 6 and carries a leaf spring 11.

Spring 11 is engaged between a pair of posts 12 carried by the drum 1 and forms a 1923. Serial No. 653,370.

resilient driving connection between the shaft and the drum.

'A brush 13 bears against the surface of the drum and makes electrical contact therewith.

The revolution of the drum causes the brush 13 to pass consecutively from one contact segment to the other.

A moment before this transition of the brush 13 takes place, one of the ribs is engaged thereby. The movement of the drum is thus arresteda The shaft 6, however, continues to rotate, thus deflecting the spring 11 of the resilient driving connection between the shaft and drum.

WVhen the tension of the spring 11 has become sufiioient to overcome the resistance caused by the ridge 5, the brush rides thereover and the drumis rotated quickly forward by the stored up energy in the spring 11.

The brush therefore passes over the insulation and onto the succeeding segment quickly, eliminating short circuiting of the segments and the drawing of an are between the brush and the receding segment on the opening of the circuit.

The switch may be used to periodically and alternately make and break an electric circult to control the contacts of a magnetic switch which may control the speed of an electric motor, as set forth in Patent No. 1,477,862, of December 18, 1923.

For this purpose a pair of brushes 14 and 15 are arranged on the opposite sides of the brush 13 in continuous electrical contact with the segments 2 and 3 of the drum respectively.

The brushes 14 and 15 are connected to one side of the magnetic windings 16 and 17 respectively of the magnetic switches 18 and 19.

The opposite side of the windings is con nected to a suitable source of current 20. The brush 13 is also connected to the source of current by conductor 21.

l Vhen the drum revolves the ma netic switches are periodically and alternate y energized as the brush passes from one segment to the other.

This causesan alternate engagement and disengagement of the contacts of the switches 18 and 19.

in Figure 3.

coiled spring'25 and isrnoved in the other direction by suitable fluid pressure admitted to the cylinder by a conduit 26.

WVhen the motor controller is used to operate a st-oker for feeding fuel to a furnace the adjustment of the brush13 ma-y befcontro'lled by the steam pressure in the boilerv feed Of course, the invention set forth herein may be embodied in different forms.

The invention is hereby claimedas follows: 1. 7 An electric switch comprising a drum, a shaft therefor, means for continuously rotating the shaft, a resilientdriving connection between the shaft and drum, a stationary contact engaging the face of said'drum, means for moving said contact, .and means carried by the drum and engaged by the, contact for momentarily arresting and accelerating the rotation of said drum. i I I 2. An electric switch comprising a drum, a

contact segment thereon, abrush for; engaging said contactingsegment, means for continuously rotating the drum, means. carried by the brush for momentarily arresting andaccelerating-the rotation of the drum with out affectingor retarding the drum rotating means, and means for automatically adjusts ing the brush longitudinally of the drurnb 8-.- An electric switch comprising a. rotatable driven memberj carrying a movable switch contact, a stationary switch: contact arranged to'have said movableswitch contact engage the same, a rota-table driving. member having a spring to rotate said driven member therefrom, and a caitchto retard said driven member as. said in vable contactis about to be disengaged from said stationary contact and therebycause said spring to accelerate said drivenmember to obtain a quick disengagement between said contacts. 1

An electric switch com-prising 'a rotatable driven member carrying a movable switch contact, astationary switch contact arranged to have said movable switch contact engage the same, a rotatable driving n'rember-having a spring to rotate said driven member therefrom, and means to retard said driven member as said movable contact is about to bedisengaged from-said stationary contact and thereby cause said spring to accelerate'said driven member to obtain a quick disengagement between said contacts.

5. An electric "switch com})ris'ing a rotatable driven member carrying two movable "drivenineniber "to obtain a switch contacts insulated from each other, a stationary switch contact having said movable contacts engage the same in succession, a rotatable driving member having a spring to rotate said driven member therefrom, and a catch to retard said driven member aseither movable contact is about to be disengaged from said stationary contact and .thereby cause said s'pring'to accelerate said quick disengagement between said contact-s. 1

6. An electricswitch comprising a rotatable driven member carrying. two movable switch contacts insulated from eachother, a stationary switchc'ontact having said movable contacts engage the samein succession,

, a rotatable driving member having a spring to rotate said driven member. therefrom, and} a catch carried by each movable contact to engage a catch carried by said stationary contact toretard said driven member as either movable contact is about to :be disengaged from' said stationary contact and thereby'causefsaid spring to accelerate said driven member to obtain a quick disengagement between said-movable and stationary contacts. 7 V V 'LAn electric switch comprising a rotatable driven member (carrying a movable switch contact, a stationary switch contact arranged to have said movable switchfcon tact engage the same, a rotatable driving member'having'aspringitoretate sa idcl-riven' member therefromra catch to retard said driven member as said movable contact is about to berlisengag'ed from saidstationary contact and thereby cause sai'd spring to ac-- celerate said driven member to obtain a quick, disengagement between said contacts, and another stationary switch contact arranged to have f said movable switch contact in continuous engagement therewith.

8. An electric switch-comprisinga rotatable driven member carrying two movable switch contacts insulated from each other, a stationary switch contact having said inovable contactsengage the sameinsuccession, arotatable driving member having; aspring to rotate said driven member therefrom, a catch-to retard said driven member as either movable contact is about to be disengaged from said stationary contact and thereby cause said spring to accelerate said driven member to obtain aquick disengagement between said contacts, and another stationary switch contact arranged to have either movable switch contact in continuous engagement therewith. V V

9. An electric switch comprising a movable driven member carrying a movable switch. contact, a stationary ,switchjcontact arranged to have said'movable switch con tact engage the *same, a movable driving member having a spring to move said driven member therefrom, and a catch to retard said driven member as said movable contact is about to be disengaged from said stationary contact and thereby cause said spring to accelerate said driven member to obtain a 5 quick disengagement between said contacts.

10. An electric switch comprising a positively driven shaft, a drum arranged upon said shaft, a resilient drive between said shaft and said drum, contact segments carried by said drum and insulated from each other, a stationary contact engaging said contact segments alternately, and means to retard the rotation of said drum momentarily against the action of said drive as a con- 35 tact segment is about to be disengaged from said stationary contact and thereby cause said drive to accelerate the rotation of said drum momentarily.

In witness whereof, I have hereunto sub- ;1 scribed my name.

JOHN M. BARR.

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